We haven't seen this issue before. Kindly share the prconfig.xml & prbootstrap.properties file along with a thread dump when the hang happens. This should provide us with details to understand the issue.
Are we sure that the BIX command line is being run with a good network access to the production database. Slow connection (network) to the database can cause such hangs.
If process is getting hanged during bootstrap load, probably the reason could be that DB connection was not returned from the pool, so you can probably check connection pooling settings. You can also put a debug logger as com.pega.pegarules.data.internal.access.ExtractImpl in prlogging.xml file which you can find in \114819_Pega718\Additional_Products\BIX\config\prlogging.xml
Once you enable the above logger to debug, There will be a message printed in the logs as "Successfully Connected to DB: " if connection is successful else it'll throw an error.